Long-term Outcomes and Prognostic Factors of Graft Failure in Penetrating Keratoplasty: A Retrospective Study at Khon Kaen Hospital

Nichawan Teerittikul

doi:10.64960/srimedj.v41i3.270716

Authors

Nichawan Teerittikul Department of Ophthalmology, Khon Kaen Hospital, Khon Kaen, Thailand 40000

DOI:

https://doi.org/10.64960/srimedj.v41i3.270716

Keywords:

penetrating keratoplasty, graft survival, therapeutic keratoplasty, large graft size, northeastern Thailand

Abstract

Background and objectives: Penetrating keratoplasty (PKP) in developing regions face unique challenges, including a high prevalence of severe infectious keratitis that often requires large-diameter grafts, as well as disparities in patient health literacy. This study aimed to evaluate the long-term graft survival outcomes, causes of failure and independent prognostic factors of PKP at a tertiary referral center in Northeastern Thailand.

Methods: A retrospective cohort study was conducted in 82 patients (82 eyes) who underwent primary PKP by a single surgeon between August 2020 and November 2025. The study was carried out at Khon Kaen Hospital, a regional tertiary center in Northeastern Thailand. Patients were classified into optical (n=31) and therapeutic (n=51) groups. Graft survival rates were estimated using the Kaplan-Meier method. Cox proportional hazards regression analysis was performed to identify independent risk factors for graft failure.

Results: The overall cumulative graft survival rates at 1 and 2 years were 53.9% and 49.0%, respectively. The optical group achieved significantly higher 1-year survival (75.0%) compared to the therapeutic group (40.4%) (Log-rank p = 0.002). Regarding the mechanisms of failure, post-operative infection was the leading direct cause (39.4%). In terms of baseline predictors, intra-operative factors, specifically a large graft size (> 8.0 mm), emerged as the strongest independent risk factor for graft failure (Hazard Ratio [HR] 6.48; 95% CI 2.66–15.79; p < 0.001), followed by donor factors, specifically older donor age (HR 1.035; 95% CI 1.01–1.06; p = 0.006).

Conclusions: While Optical PKP achieves higher survival outcomes, the prognosis for Therapeutic PKP is significantly compromised by the necessity of large-diameter trephination. Large graft size and advanced donor age, rather than therapeutic indication, are the primary determinants of failure. Strategies should aim to minimize graft size, alongside public health initiatives for early referral to prevent the need for high-risk, large-diameter keratoplasty.

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